Q. In a Young’s double-slit experiment the fringe width is $0.2mm$. If the wavelength of light used is increased by 10% and the separation between the slits is also increased by 10%, the fringe width will be
A) $0.20\ mm$
B) $0.401\ mm$
C) $0.242\ mm$
D) $0.165\ mm$
Explanation
(a) $\beta = \frac{\lambda D}{d}$; If $\lambda$ and $d$ both increase by 10%, there will be no change in fringe width $(\beta)$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.